Priority is claimed to Japanese Patent Application Number JP2004-162652 filed on May 31, 2004, the disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a circuit device and a manufacturing method thereof, and more particularly relates to a circuit device including a plurality of wiring layers laminated with an insulating layer interposed therebetween, and a manufacturing method thereof.
2. Description of the Related Art
With reference to FIGS. 16A and 16B, a description will be given of a configuration of a conventional hybrid integrated circuit device 100. This technology is described for instance in Japanese Patent Application Publication No. Hei 6 (1994)-177295. FIG. 16A is a perspective view of the hybrid integrated circuit device 100, and FIG. 16B is a cross-sectional view along the line X-X′ in FIG. 16A.
The conventional hybrid integrated circuit device 100 includes a rectangular substrate 106, and an insulating layer 107 provided on the surface of the substrate 106. On this insulating layer 107, a wiring layer 108 is patterned. Furthermore, a circuit element 104 is fixed on the wiring layer 108, and the circuit element 104 and the wiring layer 108 are electrically connected to each other by use of a thin metal wire 105. A lead 101 electrically connected to the wiring layer 108 is extended to the outside. Moreover, the entire hybrid integrated circuit device 100 is sealed with a sealing resin 102. As a method for sealing the device with the sealing resin 102, there are injection molding using a thermoplastic resin, and transfer molding using a thermosetting resin.
However, in the hybrid integrated circuit device 100 described above, formation of a single layer of wiring leads to a problem that limits a size of an electric circuit that can be integrated. As one of methods for solving this problem, there is a method for forming a multilayer structure of wirings laminated with an insulating layer interposed therebetween. The laminated wiring layers are electrically connected to each other through a connection part formed so as to penetrate the insulating layer. Moreover, in consideration of heat release properties, the insulating layer has inorganic fillers mixed therein. However, in the case where a large amount of inorganic fillers are mixed in the insulating layer in order to improve the heat release properties, there is a problem that it is difficult to form the connection part so as to penetrate the insulating layer. Specifically, it is difficult to form a multilayer wiring structure which secures the heat release properties.